Pests are more than just ugly looking critters that chew through your wiring. Many can cause serious health problems for you and your loved ones.

Mice

A common pest in most rural areas, mice may be considered easier on the eyes than the other creatures we have on this list, but they are by far one of the worst offenders when it comes to health risks. Like most pests, mice will scour your house in search of a meal; however, even if they don’t get into your food they will still contaminate your kitchen area.

Mice constantly dribble urine, meaning any surface they come into contact with instantly becomes contaminated. This steady stream means that any diseases they carry such as salmonella or meningitis, both of which can severely affect humans, will be guaranteed to find their way onto your floors and countertops. What makes this even worse is that mouse urine dries fast, becoming invisible, so you might be placing your bread down on a pile of nasty, mouse-ridden bacteria without even knowing.

Cockroaches

Roaches are a firm favorite for the most disgusting looking pests around, but while they are offensive to look at, the risks they pose to humans are even worse. Cockroaches live in sewer environments and come up into homes in search of food and warmth. While they scuttle about your countertops and kitchen cupboards they are leaving behind bacteria, parasites and pathogens, all of which can affect humans. However, roaches don’t need to contaminate a surface to harm you. They can do it simply by existing. Droppings, urine, decaying roach bodies and shed skin all break down and become air born particles— particles that can pose a serious risk to asthmatics, especially children. The floating roach dust gets into the lungs and causes allergic reactions, proving to be worse for asthma suffers than dog hair, cat fur or even conventional dust.

Bed Bugs

As it turns out, you really don’t want to let the bed bugs bite. While they are not carriers of harmful diseases or parasites, they can affect you in other ways. Not only can their bites cause rashes, scars and lesions, but they can have serious psychological effects.

Bed bugs are exactly that, bugs that live within the woodwork of your bed. Infestations are very hard to get rid of and can take a long time to destroy, leaving you to sleep in an itchy, pest-ridden bed for extended periods of time. The result of sharing your bed with these bugs can cause anxiety, stress, sleep deprivation and depression. Not only does it cause these psychological problems, but these bugs push their hosts to do whatever it takes to get rid of them. This often leads to property damage, inhalation of dangerous chemicals, and even fire hazards as sufferers resort to burning infested furniture and flooring in pure desperation.

Fleas

Fleas are flightless, but they have powerful legs and can easily jump onto your pet’s fur when they are running through an infested area, such as long grass. These tiny blood drinkers will attach themselves to anything living, including you. While their bites can give you an allergic reaction, and even cause a severe and dangerous anaphylaxis in some people, fleas can have a nastier side if accidentally swallowed. Although this is rare, mostly occurring in children, the fact they are so small means it is easy for them to become ingested. The result of ingesting these minuscule insects is a far more disturbing and harmful infestation, a tapeworm. Tapeworms are large parasitic worms that live in the intestines, munching on your food and growing up to 50 feet long.

You’re not only living creature in your home that fleas, and their potential friends, can affect. While many pet owners use some kind of flea prevention, less commonly known is that animals acquire tapeworm the same way humans do, by ingesting “infected” fleas. Any flea that has eaten tapeworm larvae and is then swallowed by your pet, typically while grooming, can turn suddenly become a far more serious problem.

Rats

We saved the best for last. Rats are carriers of some of the most dangerous diseases on the planet and without these critters the bubonic plague might not have wiped out so much of Europe.

Rats have powerful teeth and can gnaw their way through pretty much anything, allowing them to reach food and water supplies resulting in contamination. Rat fecal matter and urine can also spread numerous diseases such as leptospirosis, a debilitating illness that causes liver, kidney and heart problems. You don’t even have to consume something contaminated to become infected; simply inhaling their evaporating and decaying waste is enough. Being a larger pest than most, rats also have more aggressive tendencies and are more likely to bite and scratch humans, which could result in other infections such as rat-bite fever.